1. Field
Embodiments of the present invention generally relate to a perpendicular magnetic recording (PMR) writer for use in a hard disk drive.
2. Description of the Related Art
The heart of a computer is a magnetic disk drive which typically includes a rotating magnetic disk, a slider that has read and write heads, a suspension arm above the rotating disk and an actuator arm that swings the suspension arm to place the read and/or write heads over selected circular tracks on the rotating disk. The suspension arm biases the slider towards the surface of the disk when the disk is not rotating but, when the disk rotates, air is swirled by the rotating disk adjacent an air bearing surface (ABS) of the slider causing the slider to ride on an air bearing a slight distance from the surface of the rotating disk. When the slider rides on the air bearing, the write and read heads are employed for writing magnetic impressions to and reading magnetic signal fields from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
The write head can include a magnetic write pole and a magnetic return pole, the write pole having a much smaller cross section at the ABS than the return pole. The magnetic write pole and return pole are magnetically connected with one another at a region removed from the ABS. An electrically conductive write coil induces a magnetic flux through the write coil which results in a magnetic write field being emitted toward the adjacent magnetic medium, the write field being substantially perpendicular to the surface of the medium. The magnetic write field locally magnetizes the medium and then travels through the medium and returns to the write head at the location of the return pole where the write field is sufficiently spread out and weak so no previously recorded bits of data are erased.
The write pole is first deposited on a substrate and has a straight region and a flared region. The trench in which the write pole is deposited typically is not vertical and has a bevel angle with respect to vertical. Using conventional methods, the bevel angle increases from the end of the straight region to the end of the flared region. Thus, when the write pole on the substrate is cut at a predetermined position to define the ABS, the bevel angle at the ABS may vary depending on the cut position. In addition, more than one mask is typically used for forming the trench.
Therefore, there is a need in the art for an improved method for forming a trench for the write pole.